Neuro ICU > CIPNM

Critical Illness Polyneuropathy & Myopathy (CIPNM)

CIPNM is an umbrella term encompassing acquired neuromuscular weakness that develops in critically ill patients — including Critical Illness Polyneuropathy (CIP), Critical Illness Myopathy (CIM), and combinations of both. It is one of the most common and underrecognized complications of critical illness, affecting up to 50–60% of patients with sepsis or multi-organ failure.

CIPNM is a primary driver of ICU-acquired weakness (ICUAW) and a major contributor to Post-Intensive Care Syndrome (PICS) — prolonged functional impairment, disability, and reduced quality of life after ICU discharge. Early rehabilitation is the most effective intervention.

CIP vs. CIM: Key Differences

Feature CIP (Polyneuropathy) CIM (Myopathy)
Pathology Axonal degeneration of motor and sensory peripheral nerves Muscle fiber atrophy and necrosis; thick filament (myosin) loss
Weakness pattern Flaccid limb weakness; distal > proximal; difficulty weaning from ventilator Proximal > distal weakness; difficulty weaning from ventilator
Sensation Impaired (sensory neuropathy component) Preserved
Reflexes Reduced or absent Reduced or absent
Diagnosis EMG/NCS: reduced CMAP and SNAP amplitudes EMG/NCS: myopathic pattern; elevated CK; muscle biopsy
Prognosis Slower recovery; may persist months to years; some permanent deficit Faster recovery than CIP; often resolves over weeks to months

Risk Factors

    • Sepsis and systemic inflammatory response syndrome (SIRS) — strongest independent risk factors

    • Multi-organ failure

    • Prolonged mechanical ventilation

    • Hyperglycemia (poor glycemic control)

    • Prolonged ICU length of stay

    • Neuromuscular blocking agents (NMBAs) — particularly with prolonged use or combined with corticosteroids

    • High-dose corticosteroids

    • Prolonged immobility and bed rest

    • Aminoglycoside antibiotics

Clinical Presentation

  • Difficulty weaning from mechanical ventilation — often the first clinical sign; respiratory muscle weakness is common

  • Symmetric flaccid limb weakness — often noticed when sedation is lifted and the patient fails to move against gravity

  • Areflexia or hyporeflexia

  • Facial and bulbar muscles are typically spared (distinguishes from GBS)

  • Sensory impairment may be present (CIP) or absent (CIM)

  • Cognitive impairment is common concurrently — CIPNM often coexists with ICU delirium

Diagnosis is primarily clinical — suspect CIPNM in any patient with unexplained weakness or ventilator weaning failure after 5–7 days in the ICU. EMG/NCS can confirm and differentiate CIP from CIM.

CIPNM & Post-Intensive Care Syndrome (PICS)

CIPNM is one of the primary drivers of PICS — the constellation of physical, cognitive, and mental health impairments that persist after ICU discharge. Survivors of CIPNM may experience:

  • Profound muscle weakness lasting months to years
  • Difficulty returning to prior functional level, work, or community activities
  • Chronic fatigue and exercise intolerance
  • Neuropathic pain (in CIP)

Early and consistent rehabilitation in the ICU is the most effective intervention for reducing the long-term burden of CIPNM. See the Consequences of Prolonged Immobility and Benefits of Early Rehabilitation pages.

Therapy Implications
(Kress & Hall, 2014; Oldenburg & Hamby, 2024; Shepherd et al., 2017)

  • Early mobilization is the primary intervention. Evidence supports initiating active therapy — including sitting at edge of bed, standing, and ambulation — as early as day 1–2 of ICU admission, even in mechanically ventilated patients, when hemodynamically stable.

  • Strengthen what is available. Assess proximal vs. distal strength, upper vs. lower extremity, and respiratory muscle capacity. Tailor activity to current function — avoid overloading weak muscle groups.

  • Splinting and positioning are critical to prevent contracture during the acute phase, particularly in patients with prolonged weakness or NMBA exposure.

  • ADL as therapeutic exercise: grooming, feeding, and self-care tasks provide meaningful strengthening in the context of functional activity. Prioritize these over passive exercise alone.

  • Fatigue management: CIPNM patients fatigue rapidly. Monitor for declining performance quality, increased breathing effort, or drop in SpO₂ during sessions. Build rest breaks in proactively.

  • Communicate EMG/NCS findings to the rehab team when available — severity and type (CIP vs. CIM) inform prognosis and goal-setting conversations with the patient and family.

  • Coordinate closely with PT and SLP — ventilator weaning, respiratory muscle strengthening, and swallowing function are often simultaneously impaired.

Activity Decision Framework — CIPNM

The goal is to mobilize early and often within safe parameters. CIPNM itself is not a contraindication to therapy — hemodynamic instability, active sepsis, and respiratory compromise are the primary limiters.

Tier Clinical Status Guidance
GO Hemodynamically stable; activity order in place; RASS -1 to +1; SpO₂ >90% on current vent/O₂ settings Proceed with active therapy; match intensity to current strength level; include functional ADL tasks; progress mobility as tolerated
MODIFY Mild hemodynamic fluctuation during activity; high fatigue limiting participation; RASS -2; high ventilator support but stable Reduce intensity and duration; focus on AROM, positioning, and seated ADL; rest breaks between tasks; reassess tolerance throughout session
YIELD Active sepsis being managed; NMBA recently discontinued (within 24 hrs); activity order not in place Confirm with team before initiating upright activity; passive ROM and positioning appropriate if no contraindication; reassess as sepsis is treated
DEFER Hemodynamically unstable (vasopressor escalation, new arrhythmia); RASS < -2; FiO₂ > 60% with active titration; active NMBA infusion Hold active therapy; reassess daily; document plan for initiation when stable; splinting and passive positioning remain appropriate if cleared
STOP SpO₂ drops >4% from baseline; HR or BP outside acceptable parameters during session; acute respiratory distress; patient becomes unresponsive Stop activity; return to supine or prior position; notify nursing; document the event and parameters at time of stop

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References

Kress, J. P., & Hall, J. B. (2014). ICU-acquired weakness and recovery from critical illness. New England Journal of Medicine, 370(17), 1626–1635. https://doi.org/10.1056/NEJMra1209390

Hamby, J. R. (2024). The nervous system, part 2: Neurodegenerative diseases and other conditions. In H. Smith-Gabai & S. E. Holm (Eds.), Occupational Therapy in Acute Care (3rd ed., pp. 449–496). AOTA Press.

Shepherd, S., Batra, A., & Lerner, D. P. (2017). Review of critical illness myopathy and neuropathy. The Neurohospitalist, 7(1), 41–48. https://doi.org/10.1177/1941874416663279